Before I state this I want to say that I don't mean to brag in any way at all. Just giving some info.
I took MCAT back in 1996 (April) and didn't study at all for it. I was working on my Biochemistry degree at that time with a minor in English writing. I bought one of those review books six months before the test, read the intro and found out how the test was set up and had good intentions but never read a single thing in the book, took zero sample tests and never even heard that there were review courses for the test. My scores were V-10, P-11, B-11. I had a lot of physics and biology in my major so I think that helped a lot.
I even remember the test day, I got seat number 13 and I was extremely calm and confident when I took the test.
I did study a lot for Step I (about 24 8 hour days) though and for a couple days prior to Step II.